1. Field of the Invention
This invention relates to an air conditioner control system for a vehicle.
2. Description of the Prior Art
Conventional vehicle air conditioners generally operate in a vent mode, a bi-level mode, a heat mode, a heat/defrost mode or a defrost mode. In some vehicle air conditioners, the operational modes automatically change according to the conditions inside or outside the vehicle.
In the air conditioner disclosed in Japanese Unexamined Patent Publication No. 62(1987)-299422 (where the engine coolant is employed as the heat source), the air blow rate is gradually increased (taking into account that the temperature of the coolant is still low) to the rate at which air is blown during the automatic control, and at the same time, the operational mode of the air conditioner is successively switched between the defrost mode, the defrost/heat mode and the heat mode as the coolant temperature increases, thereby improving the defrosting effect and the leg warming effect of the air condition.
In the case of an air conditioner in which the operational mode is switched as the coolant temperature increases, it is preferable for the operational mode to be set to the heat/defrost mode when it is severely cold and the windowpane is apt to frost up. However, when there is insolation, even if the ambient temperature is extremely low the driver's head will get hot due to the hot air being discharged from the defroster vents. That is, because the altitude of the sun is low in winter, especially in northern countries, sunshine will impinge directly upon the driver's head through the windshield and heat it together with the hot air being discharged from the defroster vents.